The present invention is directed generally to a fluid processing system, and more particularly to a centrifugal biological cell processing system and apparatus for processing or reconstituting blood and other biological cells wherein fluid communication is continuously maintained with rotating wash bags without the use of rotating seals or other rotating coupling elements, thereby maintaining the system sealed and free from contamination.
In recent years long term storage of human blood has been accomplished by separating out the plasma component of the blood and freezing the remaining red blood cell component in a liquid medium such as glycerol. Prior to use the glycerolized red blood cells are thawed and pumped into a centrifugating wash chamber where, while being held in place by centrifugation, they are washed with a saline solution which displaces the glycerol preservative. The resulting reconstituted blood is then removed from the wash chamber and packaged for use.
The aforedescribed blood conditioning process necessitates the transfer of glycerolized cell and saline wash solutions into the wash chamber, and the transfer of glycerol waste and reconstituted blood from the wash chamber, while the chamber is in motion. To avoid contamination of the blood or the exposure of persons involved in the processing operation to infection, these fluid transfer operations must be carried out within a sealed pre-sterilized flow system, preferably formed of a flexible plastic or similar material which can be disposed of after each use.
One drawback present in many such flow systems has been their use of a rotating seal or coupling element between that portion of the system carried by the centrifuge rotor and that portion of the system which remains stationary. While such rotating seals have provided generally satisfactory performance, they have been expensive to manufacture and have unnecessarily added to the cost of the flow systems. Furthermore, such rotating seals do introduce an additional component into the system which if defective can cause contamination of the blood being processed. This is particularly true when two different batches of blood are being simultaneously processed since the components of one blood batch must pass side-by-side through the rotating seal with the components of another blood batch. Also, such rotating seals by reason of inherent surface wear may introduce undesirable particulate matter into the fluid being processed.
Previous attempts at overcoming the problem of a rotating seal include the use of rotating carriages on which housings were rotatably mounted. Fluid communication was established with the housings by means of umbilical cables extending to the housings and planetary motion was imparted to the housings to prevent the cables from twisting. In one such system the housing and umbilical cable were permanently sealed together, and in another such system an inner liquid processing chamber was rotatably mounted within the housing and connected to the umbilical cable by a rotating seal. Unfortunately, in the former system the liquid being processed was subjected to conflicting radial and longitudinal accelerations, necessitating the provision of capillary passageways in the chamber and thus making the system unpractable for volume processing operations. In the latter system the expensive and trouble-prone rotating seal was still present. Furthermore, neither of these systems allowed the use of more than one liquid processing chamber, preventing the simultaneous processing of multiple batches of fluids.
Thus, the need exists for a centrifugal fluid processing system and apparatus wherein multiple batches of fluid can be simultaneously and efficiently processed without the use of capillary processing chambers, or rotating coupling elements between the centrifugating processing chambers and the stationary portions of the system. In apparatus described in U.S. Pat. No. 3,586,413 to Dale A. Adams energy transfer is accomplished between fixed and rotating elements by means of a flexible umbilical cable. The present invention encompasses the application of the principle of operation of the Adam's apparatus to the centrifugation of fluids, and particularly to the centrifugation of biological fluids such as blood, and improvements in such apparatus for this purpose.